Bottom Brackets Review

  Poor misunderstood bottom bracket. The bike bottom bracket takes all of the pressure a cyclist needs to pedal and gets none of the credit.

The cylinder-shaped bike bottom bracket, using an FSA bracket as an example, is part of the bike drivetrain components that also includes a crank, or chain, set where the flat round crank with jagged edges accommodates the bike chains and an arm extending from it attaches to the bike’s pedal. Bike bottom brackets are nestled inside of a bottom bracket “shell” within the bike’s frame. And, connected to the bike’s crank set from inside that shell, bottom brackets reportedly allow the crank arms to rotate.

Bike bottom brackets like the Campagnolo bottom bracket are sold individually and as part of crank sets. Because bike bottom brackets and the shells in which they mount vary in size, it’s important to find the right fit. Cyclists might also consider different bike bottom bracket components that can affect quality, maintenance and adjustability.

Inside of a bike bottom bracket is a spindle, a grooved, or threaded, cylindrical shaped part that some refer to as an axle. The spindle, or axle, is often titanium, and it can reportedly be made either by forging, polishing after forging or machining from billet, with generally considered the least costly method. The spindle of a bike bottom brackets may also be swathed in plastic, reportedly as a means of protecting the bottom bracket from moisture.

Because of the friction that a Shimano bottom bracket or Truvativ bottom brackets endure, bottom brackets can reportedly wear out quickly, and ball bearing assemblies are found inside these and other critical bike points. With bike bottom brackets, these steel balls are generally situated within cup or cone-shaped nuts screwed on near each of the spindle’s ends. The smoother the steel surface of steel bike bearings, the smoother the feel is said to be. And some bike bottom bracket bearings are said to be more easily adjusted than others.

There are reportedly three types of bike bottom brackets, including cartridge brackets, adjustable brackets and “Ashtabula” brackets. Cartridge bottom brackets are said to be a more contemporary design, while Ashtabula brackets are said to often be found on department store bikes and older models. When evaluating SRAM bottom brackets or a Phil Wood bracket, make sure to find the exact type you want for your bike.

In terms of maintenance, cartridge brackets are considered better protected in that the steel bearings, or balls, sit inside containers. At the same time, accessing this type of bike bottom bracket reportedly requires removing the entire crank set. Cartridge bottom brackets are said to more often be removed and replaced, rather than serviced, when they were out.

Adjustable bike bottom brackets, on the other hand, are equipped with cups that, like the spindle, can reportedly be removed and replaced, and the bottom bracket cleaned, greased and adjusted as needed. With Ashtabula bottom brackets, a single piece of steel said to form the bike’s crank arm reportedly extends from one pedal to another, entering the bike bottom bracket in between.

Models

Average Pricing

The prices for individual bottom brackets can start at about $10.99 US, while bottom brackets purchased with crank sets can cost upward of $600 US.